
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <cuda_runtime.h>
#include "cuda_device_runtime_api.h"

#include "kernel.cuh"

const float table = 0;

int main(void)
{
	// Error code to check return values for CUDA calls
	cudaError_t err = cudaSuccess;

	// Print the vector length to be used, and compute its size
	int numElements = 50000;
	size_t size = numElements * sizeof(float);
	printf("[Vector addition of %d elements]\n", numElements);

	// Allocate the host input vector A
	float *h_A = (float *)malloc(size);

	// Allocate the host input vector B
	float *h_B = (float *)malloc(size);

	// Allocate the host output vector C
	float *h_C = (float *)malloc(size);

	// Verify that allocations succeeded
	if (h_A == NULL || h_B == NULL || h_C == NULL)
	{
		fprintf(stderr, "Failed to allocate host vectors!\n");
		exit(EXIT_FAILURE);
	}

	// Initialize the host input vectors
	for (int i = 0; i < numElements; ++i)
	{
		h_A[i] = rand() / (float)RAND_MAX;
		h_B[i] = rand() / (float)RAND_MAX;
	}

	// Allocate the device input vector A
	float *d_A = NULL;
	err = cudaMalloc((void **)&d_A, size);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to allocate device vector A (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Allocate the device input vector B
	float *d_B = NULL;
	err = cudaMalloc((void **)&d_B, size);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to allocate device vector B (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Allocate the device output vector C
	float *d_C = NULL;
	err = cudaMalloc((void **)&d_C, size);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to allocate device vector C (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Copy the host input vectors A and B in host memory to the device input vectors in
	// device memory
	printf("Copy input data from the host memory to the CUDA device\n");
	err = cudaMemcpy(d_A, h_A, size, cudaMemcpyHostToDevice);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to copy vector A from host to device (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	err = cudaMemcpy(d_B, h_B, size, cudaMemcpyHostToDevice);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to copy vector B from host to device (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Launch the Vector Add CUDA Kernel
	int threadsPerBlock = 256;
	int blocksPerGrid = (numElements + threadsPerBlock - 1) / threadsPerBlock;
	printf("CUDA kernel launch with %d blocks of %d threads\n", blocksPerGrid, threadsPerBlock);

	gogogo(blocksPerGrid, threadsPerBlock, d_A, d_B, d_C, numElements);
	//vectorAdd <<< blocksPerGrid, threadsPerBlock >>> (d_A, d_B, d_C, numElements);

	err = cudaGetLastError();

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to launch vectorAdd kernel (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Copy the device result vector in device memory to the host result vector
	// in host memory.
	printf("Copy output data from the CUDA device to the host memory\n");
	err = cudaMemcpy(h_C, d_C, size, cudaMemcpyDeviceToHost);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to copy vector C from device to host (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Verify that the result vector is correct
	for (int i = 0; i < numElements; ++i)
	{
		if (fabs(h_A[i] + h_B[i] - h_C[i]) > 1e-5)
		{
			fprintf(stderr, "Result verification failed at element %d!\n", i);
			exit(EXIT_FAILURE);
		}
	}

	printf("Test PASSED\n");

	// Free device global memory
	err = cudaFree(d_A);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to free device vector A (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	err = cudaFree(d_B);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to free device vector B (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	err = cudaFree(d_C);

	if (err != cudaSuccess)
	{
		fprintf(stderr, "Failed to free device vector C (error code %s)!\n", cudaGetErrorString(err));
		exit(EXIT_FAILURE);
	}

	// Free host memory
	free(h_A);
	free(h_B);
	free(h_C);

	printf("Done\n");
	return 0;
}

